CVE-2020-13345 in GitLab
Summary
by MITRE • 10/06/2020
An issue has been discovered in GitLab affecting all versions starting from 10.8. Reflected XSS on Multiple Routes
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Analysis
by VulDB Data Team • 11/16/2020
The vulnerability identified as CVE-2020-13345 represents a critical reflected cross-site scripting flaw within GitLab's web application framework. This security weakness affects all versions beginning with 10.8 and manifests across multiple routes within the platform's interface. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it in web responses. Attackers can exploit this flaw by crafting malicious URLs containing script payloads that are then reflected back to unsuspecting users who click on the compromised links.
The technical implementation of this vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications. The flaw occurs when user-provided parameters are directly incorporated into HTTP responses without proper sanitization or encoding, creating opportunities for malicious script execution in the context of the victim's browser session. Multiple routes within GitLab's application architecture are affected, indicating a systemic issue in how the platform handles parameter validation across its interface components. This widespread impact suggests that the vulnerability exists in core input handling mechanisms rather than isolated components.
The operational impact of this reflected XSS vulnerability poses significant risks to GitLab users and organizations relying on the platform for version control and collaboration. An attacker could craft malicious payloads that, when clicked by authenticated users, would execute arbitrary JavaScript code within their browser context. This could lead to session hijacking, unauthorized code modifications, data exfiltration, or redirection to malicious sites. The reflected nature of the vulnerability means that the attack payload is immediately reflected back from the server to the client, making exploitation straightforward and potentially automated through phishing campaigns or social engineering tactics. Organizations using affected GitLab versions face increased risk of unauthorized access to sensitive repositories and development environments.
Mitigation strategies for CVE-2020-13345 should prioritize immediate remediation through official GitLab security updates and patches released by the vendor. Organizations should implement comprehensive input validation and output encoding mechanisms across all web application interfaces to prevent similar vulnerabilities from persisting. The ATT&CK framework categorizes this type of vulnerability under T1203 - Exploitation for Client Execution, highlighting the need for both server-side and client-side protections. Network-level protections such as web application firewalls and content filtering systems can provide additional defense-in-depth measures while permanent fixes are implemented. Regular security assessments and penetration testing should be conducted to identify and remediate similar input validation weaknesses across the entire application stack, ensuring that all user-supplied data undergoes proper sanitization before being processed or displayed to end users.